There are in commerce many kinds of coupling for connecting to a faucet sanitary or household apparatuses that require a direct use of water: said couplings are based on screw connections, on pressure connections by hose clamps or on changes made to the faucet mouth in order to allow a connection.
It is known that household faucets in particular, and specifically bathroom and kitchen faucets, have a cylindrical housing that is generally screwed to the faucet mouth and adapted to contain an aerator. The aerator is usually inserted into the cylindrical housing from above and rarely from below; in the latter case the aerator is screwed directly to a faucet body. If the aerator is inserted from above, it rests on an abutment of the cylindrical housing. The aerator is generally composed by a mesh filter, a grill, a funnel-shaped mixing chamber and a small net. The funnel-shaped mixing chamber has side openings for the introduction of air.
A normal kit of aerator and cylindrical housing thereof does not allow a water powered apparatus to be attached to a faucet.
Generally, when one wants to connect one of these apparatuses to the faucet, he/she needs external attaching means to enable the apparatus to be connected to the faucet or he/she has to unscrew the aerator housing and add a special attachment for the specific use; he/she has to reattach the normal aerator housing after use.
By way of example, European patent application EP 0 927 850 discloses a member for the quick mounting of a gum sprinkler or the like onto a tap having a cylindrical body housing an aerator. The cylindrical body is externally provided with a thread in order to be screwed to a tap mouth and is internally provided, in its lower part, with means for the quick coupling of a connection having correspondingly shaped seats.
The same Applicant of the present patent application is the owner of the Italian patent No. 1325538, according to which an aerator housing normally screwed to the faucet mouth is replaced by another aerator housing that is adapted to be screwed externally to the faucet mouth and has in its lower part a bayonet lock that provides a secure and easy connection to a respective sanitary apparatus. Since the above bayonet lock has to be provided, the second aerator is larger than the normal component that it replaces. But this is not the biggest drawback.
U.S. Pat. No. 3,386,439 discloses an adapter that is screwed in its upper portion to a faucet mouth having an aerator housed inside it. A lower threaded portion of the adapter has a diameter smaller than the upper portion. A frusto-conical shaped portion being intermediate between the upper and lower portions, is configured to fit tightly against the surface of a cap containing a treatment liquid chamber connected with a pipe to a dental irrigator. It is clearly understood that the adapter or aerator housing on one side is connected to the faucet mouth, and on the other side to the quick attachment of the sanitary apparatus. To achieve such a connection, the adapter must have in its upper portion a thread which allows it to be screwed to the faucet mouth.
Therefore, a main problem is that the aerator housing, in which the sanitary apparatus to be connected to the faucet is inserted, must be able to be screwed at least to the majority of the faucets currently available in commerce, if not to all. However this can only be achieved by manufacturing a wide variety of aerator housings having diameters, threads for the attachment to the faucet mouth and connection means compatible with the respective household or sanitary apparatuses.
Another drawback is that the purchaser of a water powered apparatus is not always aware of the type of attachment of its own faucet and the dimensions thereof, so that he/she may be forced to forgo the purchase of a water powered household or sanitary apparatus of his/her interest.
In addition, the spread of such water powered apparatuses in welcome centres is also limited, for economic and aesthetic reasons, by the need of modifying or replacing some of the faucets.